Google's ambitious goal of converting millions of books into digital format is on hold because of copyright concerns, the company revealed recently. The search-engine giant was hoping to scan and post books from some of the nation's largest universities for viewing and searching online. Some of the books, from Harvard University, Michigan University, and Stanford University, as well as collections from the New York Public Library and Oxford University, are copyrighted, which has raised objections from the publishing community. Google is now giving publishers a chance to opt out of the effort before resuming the conversion process in November. The company's efforts at the New York Public Library and Oxford University will continue, however, because those libraries are providing Google only public-domain books that are no longer protected by copyrights. The project, which is expected to take at least 5 years to complete, is an attempt to share with the world valuable, and in many case rare, material from libraries around the world. Google is hoping to persuade other libraries to participate in the project, although it will first have to successfully navigate these copyright concerns. Publishers fear that digital versions of copyrighted books could open the publishing industry to the same types of problems experienced by the music and movie industries, which are now battling widespread online piracy.